It is well known, during the final assembly stage of a computer system or a main board of a computer system, the time/date of the CMOS real-time-clock within the system or main board must be set up to an accurate time/date data. To perform the objective, conventionally, a debug card is connected to the system through one of the ISA slots of the system. The debug card has a reference real-time-clock with accurate time/date data. This reference real-time-clock on the debug card is used to set up the time/date of the CMOS real-time-clock on the system. In typical, the debug card occupies the address D000 within the address space.
Due to expansion need of Basic Input/Output System (BIOS), it is inevitable that address D000 will be used by the BIOS in the future. If the BIOS really occupies address D000 in the future, the conventional approach used nowadays will not work any more.